Research interests: Effects of climate variability on phytoplankton composition using satellite data and global biogeochemical models. She also is working on a project addressing the effects of ice melt on the ocean biogeochemistry of the Arctic. As Rousseaux notes, “Changes in sea ice cover and runoff could potentially change the stratification, light, and nutrient levels of the Arctic waters. For example, increasing runoff in the future could deliver more nutrients and therefore support a higher production of organic matter in the waters of this region than currently observed.”

Rousseaux is a member of the Suomi National Polar-orbiting Partnership (Suomi NPP) and the Pre-Aerosol, Clouds, and ocean Ecosystem (PACE) Science Teams.

Current research focus: Effects of climate on ocean biogeochemistry, specifically on phytoplankton. This includes the effects of periodic events such as El Niño and La Niña as well as constant changes such as the effects of increasing atmospheric carbon dioxide (CO2) on the oceans.

Research findings: Rousseaux and her team detected a shift in phytoplankton composition during the El Niño to La Niña transition. Previously, researchers knew that the total phytoplankton concentration declines during El Niño events. Using the NOBM and the assimilation of SeaWiFS Ocean Color data, the team found that this decline was mostly a reflection of a decline in large, nutrient demanding phytoplankton (e.g., diatoms). While these large diatoms were declining, smaller, less nutrient-demanding cyanobacteria were able to take advantage of these conditions.